presence.py — a PURE module (no HA imports, no DB access, no timezone
logic): PresenceSchedule (child_id, cycle_length_weeks, anchor_date,
pattern mapping week index -> frozenset of present weekdays) and
PresenceOverride (child_id, inclusive start/end range, real-bool
is_present, optional note) with construction that rejects every
invalid shape up front:
- cycle length: integer 1..4 (the 4 cap mirrors schema.py's documented
CHECK); bools/floats/strings rejected.
- pattern: dict required; week indices validated as non-bool ints
covering 0..n-1 exactly (gaps and extras rejected); weekday sets
validated as ints 0..6 (bools rejected — True would silently mean
Monday; strings rejected — '02' would silently mean {0,2}); an
explicitly empty week is valid (absent all week — distinct from no
schedule, the engine's default).
- anchor/override dates: datetime.date or strict YYYY-MM-DD (strptime
round-trip; '2026-1-5' rejected).
- override range: end >= start; is_present must be a real bool;
note optional string.
- child ids: non-bool ints (SQLite binds True as 1).
Serialization: encode() emits the database's pipe-separated CSV
(sorted weekdays per week, empty segment for an absent week);
decode() derives the cycle length from the segment count (mirroring
the schema's segment-count CHECK) and validates strictly, so
decode(encode(x)) round-trips losslessly and equal patterns encode
identically. Tests: 59 (construction matrix, round-trips, encode
shapes, override coverage). Suite: 972 passed.
Joshua King
d76cde1af5